Composite materials based on g-C3N4 and TiO2 nanotubes have been synthesized as environmentally
friendly
photocatalysts with heterojunctions suitable for enhanced photocatalytic
hydrogen production. Composites were prepared with various ratios
(x = 0–1) of g-C3N4 and
after chemical modification and exfoliation of bulk g-C3N4. Contact formation between g-C3N4 and TiO2 generally enhanced photoactivity, which caused
the x-dependent changes in the photocatalytic hydrogen
evolution rates of the g-C3N4/TiO2 compounds to vary following a volcano-shaped curve with the maximum
rate at x ∼ 0.6 for all the compounds regardless
of the pretreatment (bulk or modified) of g-C3N4. The modified g-C3N4-based composites showed
higher photoactivities than the unmodified bulk g-C3N4 due to the high surface area. The major reason for the enhanced
photoactivity with the volcano shape was attributed to the Z-scheme interaction at the heterojunction. Interestingly,
detailed analysis of the kinetic H2 evolution rates of
the composites with Pt cocatalysts only on TiO2 nanotubes
further showed that the dominant type of interaction at the heterojunctions
changed from the type-II heterojunction to the Z-scheme
at x ∼ 0.1. It is inferred that structural
diversity at the g-C3N4/TiO2 interfaces
is the origin of the changes in the dominant type of interaction in
the composites with increasing ratios of g-C3N4.
Three different types of TiO2 nanoparticles in anatase and rutile phases were subject to nanosecond 532‐nm laser pulses in aqueous solution for enhanced reactivity in photocatalytic applications. Color changes observed during the laser processes resulted from laser pulse‐induced heating of TiO2 surfaces to form surface disorder with surface defects. Interestingly, TiO2 nanoparticles with different size and bulk phases undergo different changes in surface morphology, bulk phase, and defect density under the same laser pulses. The results are related with the differences in the absorption by initial defects on the TiO2 surface. Our results show that the type and density of initial defects within TiO2 matrix are important in determining subsequent thermal equilibrium‐driven changes. It is suggested that nanosecond laser pulses with energies lower than the bandgap of the semiconductor materials provide a chance for selective modification of oxide nanomaterials such as TiO2 for a new photoresponsive functionality in diverse applications.
Highly efficient heterojunctions by combining n-type g-C3N4 and MOFs as bi-functional photoelectrocatalysts towards the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.